Devices and methods for HARQ-ACK feedback scheme on PUSCH in wireless communication systems

ABSTRACT

Devices and methods of reducing overall Hybrid Automatic Repeat Request-Acknowledgment (HARQ-ACK) of user equipment (UE) using a large amount of carrier aggregation are generally described. The UE may receive a subframe from an enhanced NodeB (eNB). The subframe may contain a physical downlink control channel (PDCCH) formed in accordance with a Downlink Control information (DCI) format. The DCI format may comprise a Downlink Assignment Index (DAI) for Time Division Duplexed (TDD) and Frequency Division Duplexed (FDD) operation. The UE may determine, dependent on the DAI, a number and ordering of Hybrid Automatic Repeat Request-Acknowledgment (HARQ-ACK) bits to be transmitted on a Physical Uplink Shared Channel (PUSCH) and subsequently transmit the HARQ-ACK bits.

PRIORITY CLAIM

This application is a continuation of U.S. patent application Ser. No.14/751,054, filed Jun. 25, 2015, which claims the benefit of priority toU.S. Provisional Patent Application Ser. No. 62/105,850, filed Jan. 21,2015, and entitled “NOVEL HARQ-ACK FEEDBACK SCHEME ON PUSCH IN WIRELESSCOMMUNICATION SYSTEMS,” each of which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

Embodiments pertain to radio access networks. Some embodiments relate toHybrid Automatic Repeat Request-Acknowledgment (HARQ-ACK) mechanisms incellular networks, including Third Generation Partnership Project LongTerm Evolution (3GPP LTE) networks and LTE advanced (LTE-A) networks aswell as 4^(th) generation (4G) networks and 5^(th) generation (5G)networks.

BACKGROUND

With the ever increasing desire for faster data rates, notably throughlong-term evolution-Advanced (LTE-A) networks in Release 10, systemdesigners have turned several different techniques such as multipleinput multiple output (MIMO), cooperative multiple point transmission(CoMP) and carrier aggregation. Carrier aggregation increases bandwidth,and thus bitrate, by aggregating multiple carriers to form a largeroverall transmission bandwidth. The explosive increase in mobile dataconsumption has led to a LTE deployment and carrier aggregation in theunlicensed spectrum (LTE-Unlicensed (LTE-U), with UEs using the LTE-Uband referred to as License Assisted Access (LAA) UEs). With increasingcarrier aggregation, the HARQ-ACK response may take up a large amount ofoverhead.

It would be desirable to minimize the HARQ-ACK overhead whilemaintaining HARQ-ACK performance.

BRIEF DESCRIPTION OF THE FIGURES

In the figures, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The figures illustrate generally, by way of example, but notby way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 shows an example of a portion of an end-to-end networkarchitecture of an LTE network with various components of the network inaccordance with some embodiments.

FIG. 2 illustrates a functional block diagram of a communication devicein accordance with some embodiments.

FIG. 3 shows Frequency Division Duplexed (FDD) legacy Downlink Controlinformation (DCI) format adjustments according to some embodiments.

FIG. 4 illustrates Downlink Assignment Index (DAI) field usage in DCIformats according to some embodiments.

FIG. 5 illustrates a HARQ-ACK construction using Downlink AssignmentIndex (DAI) fields according to some embodiments.

FIG. 6 shows Time Division Duplexed (TDD) legacy DCI format adjustmentsaccording to some embodiments.

FIG. 7 illustrates DAI-2 and DAI field settings according to someembodiments.

FIG. 8 illustrates DAI-2 and DAI determination according to someembodiments.

FIG. 9 illustrates a flowchart of a method of using a HARQ-ACKtransmission with reduced overhead in accordance with some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

FIG. 1 shows an example of a portion of an end-to-end networkarchitecture of a Long Term Evolution (LTE) network with variouscomponents of the network in accordance with some embodiments. As usedherein, an LTE network refers to both LTE and LTE Advanced (LTE-A)networks as well as other versions of LTE networks to be developed. Thenetwork 100 may comprise a radio access network (RAN) (e.g., asdepicted, the E-UTRAN or evolved universal terrestrial radio accessnetwork) 101 and core network 120 (e.g., shown as an evolved packet core(EPC)) coupled together through an S interface 115. For convenience andbrevity, only a portion of the core network 120, as well as the RAN 101,is shown in the example.

The core network 120 may include a mobility management entity (MME) 122,serving gateway (serving GW) 124, and packet data network gateway (PDNGW) 126. The RAN 101 may include eNBs 104 (which may operate as basestations) for communicating with UE 102. The eNBs 104 may include macroeNBs and low power (LP) eNBs.

The MME 122 may be similar in function to the control plane of legacyServing GPRS Support Nodes (SGSN). The MME 122 may manage mobilityaspects in access such as gateway selection and tracking area listmanagement. The serving GW 124 may terminate the interface toward theRAN 101, and route data packets between the RAN 101 and the core network120. In addition, the serving GW 124 may be a local mobility anchorpoint for inter-eNB handovers and also may provide an anchor forinter-3GPP mobility. Other responsibilities may include lawfulintercept, charging, and some policy enforcement. The serving GW 124 andthe MME 122 may be implemented in one physical node or separate physicalnodes. The PDN GW 126 may terminate an SGi interface toward the packetdata network (PDN). The PDN GW 126 may route data packets between theEPC 120 and the external PDN, and may perform policy enforcement andcharging data collection. The PDN GW 126 may also provide an anchorpoint for mobility devices with non-LTE access. The external PDN can beany kind of IP network, as well as an IP Multimedia Subsystem (IMS)domain. The PDN GW 126 and the serving GW 124 may be implemented in asingle physical node or separate physical nodes.

The eNBs 104 (macro and micro) may terminate the air interface protocoland may be the first point of contact for a UE 102. In some embodiments,an eNB 104 may fulfill various logical functions for the RAN 101including, but not limited to, RNC (radio network controller functions)such as radio bearer management, uplink and downlink dynamic radioresource management and data packet scheduling, and mobility management.In accordance with embodiments, UEs 102 may be configured to communicateorthogonal frequency division multiplexed (OFDM) communication signalswith an eNB 104 over a multicarrier communication channel in accordancewith an OFDMA communication technique. The OFDM signals may comprise aplurality of orthogonal subcarriers.

The S1 interface 115 may be the interface that separates the RAN 101 andthe EPC 120. It may be split into two parts: the S1-U, which may carrytraffic data between the eNBs 104 and the serving GW 124, and theS1-MME, which may be a signaling interface between the eNBs 104 and theMME 122. The X2 interface may be the interface between eNBs 104. The X2interface may comprise two parts, the X2-C and X2-U. The X2-C may be thecontrol plane interface between the eNBs 104, while the X2-U may be theuser plane interface between the eNBs 104.

With cellular networks, LP cells may be typically used to extendcoverage to indoor areas where outdoor signals do not reach well, or toadd network capacity in areas with dense usage. In particular, it may bedesirable to enhance the coverage of a wireless communication systemusing cells of different sizes, macrocells, microcells, picocells, andfemtocells, to boost system performance. The cells of different sizesmay operate on the same frequency band, such as the LTE unlicensed band,or may operate on different frequency bands with each cell operating ina different frequency band or only cells of different sizes operating ondifferent frequency bands. As used herein, the term low power (LP) eNBrefers to any suitable relatively low power eNB for implementing anarrower cell (narrower than a macro cell) such as a femtocell, apicocell, or a microcell. Femtocell eNBs may be typically provided by amobile network operator to its residential or enterprise customers. Afemtocell may be typically the size of a residential gateway or smallerand generally connect to a broadband line. The femtocell may connect tothe mobile operator's mobile network and provide extra coverage in arange of typically 30 to 50 meters. Thus, a LP eNB might be a femtocelleNB since it is coupled through the PDN GW 126. Similarly, a picocellmay be a wireless communication system typically covering a small area,such as in-building (offices, shopping malls, train stations, etc.), ormore recently in-aircraft. A picocell eNB may generally connect throughthe X2 link to another eNB such as a macro eNB through its base stationcontroller (BSC) functionality. Thus, LP eNB may be implemented with apicocell eNB since it may be coupled to a macro eNB via an X2 interface.Picocell eNBs or other LP eNBs may incorporate some or all functionalityof a macro eNB. In some cases, this may be referred to as an accesspoint base station or enterprise femtocell.

Communication over an LTE network may be split up into 10 ms frames,each of which may contain ten 1 ms subframes. Each subframe of theframe, in turn, may contain two slots of 0.5 ms. Each subframe may beused for uplink communications from the UE to the eNB or downlinkcommunications from the eNB to the UE. In one embodiment, the eNB mayallocate a greater number of downlink communications than uplinkcommunications in a particular frame. The eNB may schedule transmissionsover a variety of frequency bands (f₁ and f₂). The allocation ofresources in subframes used in one frequency band and may differ fromthose in another frequency band. Each slot of the subframe may contain6-7 symbols, depending on the system used. In one embodiment, thesubframe may contain 12 subcarriers. A downlink resource grid may beused for downlink transmissions from an eNB to a UE, while an uplinkresource grid may be used for uplink transmissions from a UE to an eNBor from a UE to another UE. The resource grid may be a time-frequencygrid, which is the physical resource in the downlink in each slot. Thesmallest time-frequency unit in a resource grid may be denoted as aresource element (RE). Each column and each row of the resource grid maycorrespond to one OFDM symbol and one OFDM subcarrier, respectively. Theresource grid may contain resource blocks (RBs) that describe themapping of physical channels to resource elements and physical RBs(PRBs). A PRB may be the smallest unit of resources that can beallocated to a UE. A resource block may be 180 kHz wide in frequency and1 slot long in time. In frequency, resource blocks may be either 12×15kHz subcarriers or 24×7.5 kHz subcarriers wide. For most channels andsignals, 12 subcarriers may be used per resource block, dependent on thesystem bandwidth. In Frequency Division Duplexed (FDD) mode, both theuplink and downlink frames may be 10 ms and frequency (full-duplex) ortime (half-duplex) separated. In Time Division Duplexed (TDD), theuplink and downlink subframes may be transmitted on the same frequencyand are multiplexed in the time domain. The duration of the resourcegrid in the time domain corresponds to one subframe or two resourceblocks. Each resource grid may comprise 12 (subcarriers)*14(symbols)==168 resource elements.

There may be several different physical downlink channels that areconveyed using such resource blocks, including the physical downlinkcontrol channel (PDCCH) and the physical downlink shared channel(PDSCH). Each subframe may contain a PDCCH, physical hybrid-ARQindicator channel (PHICH), physical control format indicator channel(PCFICH) and the PDSCH. The PDCCH may normally occupy the first up tothree symbols (four in the case of narrow bandwidths of 1.4 MHz) of eachsubframe and carry, among other things, information about the transportformat and resource allocations related to the PDSCH channel and uplinkscheduling grants for a physical uplink shared channel (PUSCH)transmission. The PHICH may be used to signal HARQ information inresponse to a PUSCH transmission. The PCFICH may inform the UE thecontrol region size (e.g. one, two or three OFDM symbols) in eachdownlink subframe. The PDSCH may carry user data and higher layersignaling to a particular UE and occupy the remainder of the downlinksubframe to avoid the resources in which downlink control channels(PDCCH/PHICH/PCFICH) are transmitted. Typically, downlink scheduling(assigning control and shared channel resource blocks to UEs within acell) may be performed at the eNB based on channel quality informationprovided by the UEs, and then the downlink resource assignmentinformation may be sent to a scheduled UE on the PDCCH used for(assigned to) PDSCH reception of the UE.

The PDCCH may contain downlink control information (DCI) in one of anumber of formats that tell the UE where to find and how to decode thedata, transmitted on PDSCH in the same subframe, from the resource grid.The DCI may provide details such as the number of resource blocks,resource allocation type, modulation scheme, transport block, redundancyversion, coding rate etc. Each DCI format may have a cyclic redundancycode (CRC) and be scrambled with a Radio Network Temporary Identifier(RNTI) that identifies the target UE for which the PDSCH is intended.Use of the RNTI, which may be UE-specific, may limit decoding of the DCIinformation (and hence the corresponding PDSCH) to only the intended UEThe PDCCH may be located in any of a number of frequency/temporalregions, depending on whether the PDCCH is UE-Specific or common, aswell as the aggregation level. The set of possible candidate locationsfor the PDCCH is defined in terms of search spaces. A search space isdefined by a set of Control Channel Element (CCE) candidates with anumber of aggregation level Lϵ{1, 2, 4, 8} where the UE may monitor tofind its PDCCHs. A common search space may carry DCIs that are commonfor all UEs, for example, system information (using the SI-RNTI), paging(P-RNTI), PRACH responses (RA-RNTI), or UL TPC commands(TPC-PUCCH/PUSCH-RNTI). A UE-specific search space may carry DCIs forUE-specific allocations using a Cell Radio-Network Temporary Identifier(C-RNTI) assigned to the UE, a semi-persistent scheduling (SPS C-RNTI),or an initial allocation (temporary C-RNTI). When configuring an SPS(either uplink or downlink), the SPS C-RNTI is provided by the eNB andthe UE is configured by higher layers to decode a PDCCH with a CRCscrambled by the SPS C-RNTI. The UE may monitor the PDCCH having a CRCscrambled by the SPS C-RNTI in every subframe as the eNB canactivate/re-activate/release the SPS at any time using a DCI format witha CRC scrambled by an SPS C-RNTI. The received DCI format with a CRCscrambled by the SPS C-RNTI can be a grant/assignment for aretransmission or for activation/re-activation/release of the SPS. 3GPPTechnical Specification 36.213 has tabulated the validation procedurefor activation/re-activation/release of SPS.

In addition to the PDCCH, an enhanced PDCCH (EPDCCH) may be used by theeNB and UE. The PDSCH may thus contain data in some of the resourceblocks (RBs) and then EPDCCH contains the downlink control signals inothers of the RBs of the bandwidth supported by the UE. Different UEsmay have different EPDCCH configurations. The sets of RBs correspondingto EPDCCH may be configured, for example, by higher layer signaling suchas Radio Resource Control (RRC) signaling for EPDCCH monitoring.

The Physical Uplink Control Channel (PUCCH) may be used by the UE tosend Uplink Control Information (UCI) to the eNB. The PUCCH may bemapped to an UL control channel resource defined by an orthogonal covercode and two resource blocks (RBs), consecutive in time, with hoppingpotentially at the boundary between adjacent slots. The PUCCH may takeseveral different formats, with the UCI containing information dependenton the format. Specifically, the PUCCH may contain a scheduling request(SR), acknowledgement responses/retransmission requests (ACK/NACK) or aChannel Quality Indication (CQI)/Channel State Information (CSI). TheCQI/CSI may indicate to the eNB an estimate of the current downlinkchannel conditions as seen by the UE to aid channel-dependent schedulingand, if one MIMO transmission mode is configured to the UE, may includeMIMO-related feedback (e.g. Precoder matrix indication, PMI).

In order to enable retransmission of missing or erroneous data unites,the Hybrid Automatic Repeat Request (HARQ) scheme may be used to providethe feedback on success or failure of the decoding attempt to thetransmitter after each received data block. When an eNB sends PDSCH datain a downlink transmission to the UE, the data packets may be senttogether with indicators in a PDCCH in the same subframe that inform theUE about the scheduling of the PDSCH, including the transmission timeand other scheduling information of the transmitted data. For each PDSCHcodeword that the UE receives, the UE may respond with an ACK when thecodeword is successfully decoded, or a NACK when the codeword is notsuccessfully decoded. The eNB may expect the ACK/NACK feedback after apredetermined number of subframes from the subframe in which the PDSCHdata is sent. Upon receiving a NACK from the UE, the eNB may retransmitthe transport block or skip the retransmission if the retransmissionnumber exceeds a maximum value. The ACK/NACK for the corresponding thePDSCH may be transmitted by the UE four subframes after the PDSCH isreceived from the eNB. Depending on the number of codewords present,HARQ-ACK information corresponding to a PDSCH may contain, for example,1 or 2 information bits (DCI formats 1a and 1b, respectively). TheHARQ-ACK bits may then be processed, as per the PUCCH.

A scheduling request (SR) may permit the UE to request uplink resourcesfor Physical Uplink Shared Channel (PUSCH). In some embodiments, noinformation bits are transmitted by the UE to request uplink resourcesto transmit PUSCH. The eNB may know, however, the timing of when toexpect a scheduling request from each UE within the cell as theresources used for SR transmission for a given UE is assigned by eNB,occurring every several subframes. Thus, if PUCCH energy is detected,the eNB may identify it as a scheduling request from the correspondingUE PUCCH formats 1, 1a, and 1b may use four SC-FDMA symbols of sevenOFDM symbols per slot to transmit HARQ-ACK information bits using anormal cyclic prefix (CP) and may be modulated respectfully using binaryphase shift keying (BPSK) and quadrature phase shift keying (QPSK). If anormal CP is used, the remaining 3 symbols may be used for a PUCCHdemodulation reference signal (DM-RS). If a sounding reference signal(SRS) overlaps the PUCCH symbols, only three symbols of the seven OFDMsymbols may be used for HARQ-ACK information bits transmission in thesecond slot of the subframe. DM-RS symbols may be used by the eNB toperform channel estimation and allow for coherent demodulation of thereceived signal. The DM-RS symbols may be essentially pilot symbols inLTE, used for channel estimation for the demodulation of the datasymbols of the subframe.

FIG. 2 illustrates a functional block diagram of a communication device(e.g., an UE or eNB) in accordance with some embodiments. Thecommunication device 200 may include physical layer (PHY) circuitry 202for transmitting and receiving radio frequency electrical signals to andfrom the communication device, other eNBs, other UEs or other devicesusing one or more antennas 201 electrically connected to the PHYcircuitry. The PHY circuitry 202 may include circuitry formodulation/demodulation, upconversion/downconversion, filtering,amplification, etc. Communication device 200 may also include mediumaccess control layer (MAC) circuitry 204 for controlling access to thewireless medium and to configure frames or packets for communicatingover the wireless medium. The communication device 200 may also includeprocessing circuitry 206 and memory 208 arranged to configure thevarious elements of the cellular device to perform the operationsdescribed herein. The memory 208 may be used to store information forconfiguring the processing circuitry 206 to perform the operations. Insome embodiments, the physical layer (PHY) circuitry 202 may contain atransceiver connected with and controlled by the processing circuitry206.

In some embodiments, the communication device 200 may be part of aportable wireless communication device, such as a personal digitalassistant (PDA), a laptop or portable computer with wirelesscommunication capability, a web tablet, a wireless telephone, asmartphone, a wireless headset, a pager, an instant messaging device, adigital camera, an access point, a television, a medical device (e.g., aheart rate monitor, a blood pressure monitor, etc.), a wearable device,a sensor, or other device that may receive and/or transmit informationwirelessly. In some embodiments, the communication device 200 mayinclude one or more of a keyboard, a display, a non-volatile memoryport, multiple antennas, a graphics processor, an application processor,speakers, and other mobile device elements. The display may be an LCDscreen including a touch screen.

The one or more antennas 201 utilized by the communication device 200may comprise one or more directional or omnidirectional antennas,including, for example, dipole antennas, monopole antennas, patchantennas, loop antennas, microstrip antennas or other types of antennassuitable for transmission of RF signals. In some embodiments, instead oftwo or more antennas, a single antenna with multiple apertures may beused. In these embodiments, each aperture may be considered a separateantenna. In some multiple-input multiple-output (MIMO) embodiments, theantennas may be effectively separated to take advantage of spatialdiversity and different channel characteristics that may result betweeneach of the antennas of a receiving station and each of the antennas ofa transmitting station. In some MIMO embodiments, the antennas may beseparated by up to 1/10 of a wavelength or more.

Although the communication device 200 is illustrated as having severalseparate functional elements, one or more of the functional elements maybe combined and may be implemented by combinations ofsoftware-configured elements, such as processing elements includingdigital signal processors (DSPs), and/or other hardware elements. Forexample, some elements may comprise one or more microprocessors, DSPs,application specific integrated circuits (ASICs), radio-frequencyintegrated circuits (RFICs), and combinations of various hardware andlogic circuitry for performing at least the functions described herein.In some embodiments, the functional elements may refer to one or moreprocesses operating on one or more processing elements.

The embodiments described may be implemented in one or a combination ofhardware, firmware and software. Embodiments may also be implemented asinstructions stored on a computer-readable storage medium, which may beread and executed by at least one processor to perform the operationsdescribed herein. A computer-readable storage medium may include anynon-transitory mechanism for storing information in a form readable by amachine (e.g., a computer). For example, a computer-readable storagemedium may include read-only memory (ROM), random-access memory (RAM),magnetic disk storage media, optical storage media, flash-memorydevices, and other storage devices and media. In these embodiments, oneor more processors may be configured with the instructions to performthe operations described herein.

In some embodiments, the processing circuitry 206 may be configured toreceive OFDM communication signals over a multicarrier communicationchannel in accordance with an OFDMA communication technique. The OFDMsignals may comprise a plurality of orthogonal subcarriers. In somebroadband multicarrier embodiments, the cellular device 200 may operateas part of a broadband wireless access (BWA) network communicationnetwork, such as a Worldwide Interoperability for Microwave Access(WiMAX) communication network or a 3^(rd) Generation Partnership Project(3GPP) Universal Terrestrial Radio Access Network (UTRAN) or a LTEcommunication network, an LTE-Advanced communication network, a fifthgeneration (5G) or later LTE communication network or a high speeddownlink/uplink access (HSDPA/HSUPA) communication network, although thescope of the invention is not limited in this respect.

Carrier aggregation, until recently, has been limited by 3GPPspecification to aggregate up to five component carriers, which has beenincreased to thirty two in 3GPP Release 13 to effect enhanced carrieraggregation. One issue in support the enhanced carrier aggregation withup to 32 CCs involves design of uplink transmissions to avoidunnecessary performance loss of a PUSCH transmission due to a hugeamount of redundant HARQ-ACK information bits on the PUSCH. In moredetail, the UCI may be transmitted using the PUCCH, but sometimes may bepiggybacked using the PUSCH instead of PUCCH for a particular type ofUE, e.g. when the PUSCH is to be transmitted in an uplink subframe andthe UE is incapable of simultaneous PUCCH and PUSCH transmission. Whenthe UCI is transmitted on the PUSCH, the Channel Quality Indicator (CQI)and Pre-coding Matrix Indicator (PMI), which indicate the channelquality, may be transmitted at the beginning of uplink shared channel(UL-SCH) data resources and mapped sequentially to all single-carrierfrequency division multiple access (SC-FDMA) symbols on one subcarrierbefore continuing on the next subcarrier. The UL-SCH data israte-matched around the CQI/PMI data. However, the HARQ-ACK informationbits/symbols are mapped to SC-FDMA symbols by puncturing the mappedPUSCH data resource elements (REs), which may degrade the PUSCHperformance once it presents.

In recent 3GPP LTE releases, the HARQ-ACK codebook size may bedetermined by the number and transmission mode of configured servingcells (also referred to as component carriers (CC)) and the number ofdownlink subframes in the bundled window (i.e. containing multiplesubframe(s) associated with a particular uplink frame that carry thecorresponding HARQ-ACK information bits). The HARQ-ACK codebook mayinclude a number of HARQ-ACK bits equal to the number of configuredserving cells multiplied by the number of transport blocks, which maythus contain redundant HARQ-ACK bits information in some cases asexplained following. The existing HARQ-ACK codebook size determinationmethod may not be able to minimize the HARQ-ACK overhead with theincreased CC numbers, especially in circumstances in which the enhancedNode-B (eNB) only schedules a small portion of configured serving cellsfor LAA PDSCH transmission due to the opportunistic nature of the LAAcommunications.

Due to the excessive overhead when a large amount of carrier aggregationis used in the system (e.g., greater than 10-15 carrier components orserving cells), it may be desirable to minimize the HARQ-ACK payloadsize on the PUSCH while maintaining HARQ-ACK performance when the UE isconfigured with massive serving cells on unlicensed spectrum. A newmechanism may thus be employed to reduce the size of the HARQ-ACK bits,as well as ordering the HARQ-ACK bits to avoid ambiguity in theassociation between the HARQ-ACK bits and corresponding componentcarriers/transport blocks. To this end, in some embodiments a new fieldmay be added to legacy DCI formats used for PUSCH and PDSCH schedulingin both Frequency Division Duplexing (FDD) and Time Division Duplexing(TDD) communications. As used herein, legacy DCI formats are formatsused in 3GPP Release 12 (or earlier) systems. Relying on new informationelements (IEs) in 3GPP Rel-13 DCI formats, a new HARQ-ACK bitsdetermination and mapping method may be used to address the overheadissue with HARQ-ACK bits on the PUSCH when a large amount of carrieraggregation is configured for a particular UE.

For FDD communications, as indicated above, the UE may receive a PDSCHor PDCCH transmission indicating a downlink SPS release in subframe n-4that is intended for the UE (on the UE specific search space given bythe C-RNTI). In response, the UE may transmit an ACK/NACK in the uplinksubframe n, four subframes later. FIG. 3 shows FDD legacy DCI formatadjustments according to some embodiments. In particular, FIG. 3 showsmodifications (in this case additions) to legacy DCI formats 0/4 312 andlegacy DCI formats 1/1A/1B/1D/2/2A/2B/2C/2D 322 to form new DCI formats.In particular, different IEs, referred to herein as Downlink AssignmentIndexes (DAI) 314, 324, may be respectively added to the legacy DCIformats 312, 322 to form the new DCI formats 310, 320. This may minimizethe payload size of the HARQ-ACK bits when the UE transmits HARQ-ACKinformation bits on the PUSCH, adjusted based on a detected PDCCH withone of the DCI formats intended for the UE and the UE is configured withmore than one serving cell.

As shown in FIG. 3, the DAI field 314 for DCI formats 0/4 may contain Xbits for FDD operation. In some embodiments, X may be 2, 3 or 4,representing a balance between adding additional overhead to the controlsignaling and reducing the probability that the UE falsely derived thetotal number of HARQ-ACK bits. As above, the DAI field 314 may belimited to DCI format 0/4, mapped onto the UE specific search spacegiven by the CRC parity bits scrambled with the C-RNTI. The value of theDAI in DCI format 0/4, V_(DAI) ^(UL), may be determined by the UEaccording to Table 1 (for a 2-bit DAI), Table 2 (for a 3-bit DAI) andTable 3 (for a 4-bit DAI), in subframe n-4.

TABLE 1 Value of 2-bit Downlink Assignment Index Number of subframes/CCsDAI V_(DAI) ^(UL) with PDSCH transmission and MSB, LSB or V_(DAI) ^(DL)with PDCCH indicating DL SPS release 0, 0 1 1 or 5 or 9 or 13 or 17 or21 or 25 or 29 0, 1 2 2 or 6 or 10 or 14 or 18 or 22 or 26 or 30 1, 0 33 or 7 or 11 or 15 or 19 or 23 or 27 or 31 1, 1 4 0/4 or 8 or 12 or 16or 20 or 24 or 28 or 32

TABLE 2 Value of 3-bit Downlink Assignment Index Number DAI V_(DAI)^(UL) of subframes/CCs with PDSCH transmission MSB, LSB or V_(DAI) ^(DL)and with PDCCH indicating DL SPS release 0, 0, 0 1 1 or 9 or 17 or 25 0,0, 1 2 2 or 10 or 18 or 26 0, 1, 0 3 3 or 11 or 19 or 27 0, 1, 1 4 4 or12 or 20 or 28 1, 0, 0 5 5 or 13 or 21 or 29 1, 0, 1 6 6 or 14 or 22 or30 1, 1, 0 7 7 or 15 or 23 or 31 1, 1, 1 8 0 or 8 or 16 or 24 or 32

TABLE 3 Value of 4-bit Downlink Assignment Index Number of subframes/CCswith DAI PDSCH transmission and MSB, LSB V_(DAI) ^(UL) or V_(DAI) ^(DL)with PDCCH indicating DL SPS release 0, 0, 0, 0 1 1 or 17 0, 0, 0, 1 2 2or 18 0, 0, 1, 0 3 3 or 19 0, 0, 1, 1 4 4 or 20 0, 1, 0, 0 5 5 or 21 0,1, 0, 1 6 6 or 22 0, 1, 1, 0 7 7 or 23 0, 1, 1, 1 8 8 or 24 1, 0, 0, 0 99 or 25 1, 0, 0, 1 10 10 or 26  1, 0, 1, 0 11 11 or 27  1, 0, 1, 1 12 12or 28  1, 1, 0, 0 13 13 or 29  1, 1, 0, 1 14 14 or 30  1, 1, 1, 0 15 15or 31  1, 1, 1, 1 16 0 or 16 or 32

The DCI format 0/4 value DAI, V_(DAI) ^(UL), may represent the totalnumber of serving cells or CCs with PDSCH transmissions and with aPDCCH/EPDCCH transmission indicating a downlink SPS release to thecorresponding UE in subframe n-4. In some embodiments, the DCI format0/4 value DAI may indicate the number of subframes containing a PDSCHtransmission and PDCCH transmission indicating a downlink SPS releaseacross all serving cells. As shown in Table 1, for example, for acarrier aggregation of 32 CCs, each 2-bit DCI format 0/4 value mayindicate one of 8 possible subframe/CC numbers with a PDSCH transmissionand with PDCCH indicating a downlink SPS release, so that a DCI format0/4 value of i (where i is one of the 4 possible 2-bit values) mayindicate one of i+4m subframes/CCs with a PDSCH transmission and withPDCCH indicating a downlink SPS release, where m is an integer between0-7. Similarly, as shown in Table 2, each 3-bit DCI format 0/4 value mayindicate one of 3 possible subframe/CC numbers with PDSCH transmissionand with PDCCH indicating a downlink SPS release, so that a DCI format0/4 value of i (where i is one of the 8 possible 3-bit values) mayindicate i+8m subframes/CCs with a PDSCH transmission and with PDCCHindicating a downlink SPS release, where m is an integer between 0-3. Asshown in Table 3, each 4-bit DCI format 0/4 value may indicate one of 2possible subframe/CC numbers with a PDSCH transmission and with a PDCCHindicating a downlink SPS release, so that a DCI format 0/4 value of i(where i is one of the 16 possible 4-bit values) may indicate i+16msubframes/CCs with a PDSCH transmission and with a PDCCH indicating adownlink SPS release, where m is an integer between 0-1. The value ofDAI field in a DCI format 0/4 may thus include all PDSCH transmissions(i.e., those with and without a corresponding PDCCH transmission) withinthe configured serving cells in subframe n-4. In some embodiments, asshown in Tables 2-4, if neither a PDSCH transmission, nor a PDCCHtransmission indicating the downlink SPS resource release is intendedfor the UE, the UE may be able to expect that the value of the DAI inDCI format 0/4, V_(DSI) ^(UL), if transmitted, is set to 4 if a 2-bitDAI is used, set to 8 if 3-bit DAI is used, or set to 16 if 4-bit DAI isused.

The DAI field 324 for DCI formats 1/1A/1B/1D/2/2A/2B/2C/2D may contain Ybits for FDD operation, where Y may be the same as or different from X.Similar to the DAI field 314, the DAI field 324 may be limited to DCIformats scheduling a PDSCH that are mapped onto the UE specific searchspace given by the C-RNTI. The value of the DAI in DCI formats1/1A/1B/1D/2/2A/2B/2C/2D, V_(DAI,k) ^(DL), may indicate an accumulativenumber of PDCCH/EPDCCH(s) with assigned PDSCH transmission(s) andPDCCH/EPDCCH(s) indicating downlink SPS release in the serving cells insubframe n-4. This value may be updated from serving cell to servingcell in subframe n-4.

When a received V_(DAI,k) ^(DL) in serving cell k is smaller than anearlier received V_(DAI,i) ^(DL) in serving cell i, where i<k, the UEmay calculate the associated DAI value as: DAI=V_(DAI) ^(DL)+2^(Y),otherwise, the UE calculate DAI as: DAI=V_(DAI) ^(DL), where Y is thenumber of bits of the DAI field 324 and V_(DAI) ^(DL) is determinedbased on 2/3/4-bit DAI field in DCI formats respectively according toTable 1/2/3. N_(SPS), which can be zero or one, may be the number ofPDSCH transmissions without a corresponding PDCCH in subframe n-4. Thismay be updated from serving cell to serving cell.

FIG. 4 illustrates DAI field usage in DCI formats according to someembodiments. In FIG. 4, a 2-bit DAI field setting in the DCI format 0/4430 and DCI format 1A 440 is shown, assuming the eNB serving the UEschedules seven PDSCH transmissions in subframe n-4 410 for a given UEin the ten serving cells (i.e. carriers) 412, which includes one SPSPDSCH. The arrow in subframe n-4 indicates that the CC carries adownlink transmission. As can be seen the PDSCH transmissions arescheduled in CCs 1, 3 (the SPS), 5, 6, 7, 8 and 10. The DAI value in DCIformats used for scheduling the PDSCH in subframe n-4 may be accumulatedstarting from 0 in ascending order of the downlink CC that has PDSCHscheduling. Following this rule, the DAI value in CC 1 is 00, in CC5 is01 (skipping the CC that contains the SPS PDSCH transmission), in CC 6is 10, in CC 7 is 11, in CC 7 is 00 and in CC 10 is 01. As above, theDAI value resets after the fourth CC as only four DAI values areavailable for a 2-bit DAI field. In some embodiments, because sevenPDSCH transmissions are scheduled in subframe n-4 410, the value of theDAI in DCI format 0/4, V_(DAI) ^(UL), from Table 1 is 3 due to thelimitation of 2-bit DAI field size.

In some embodiments, if the PUSCH transmission in subframe n 420 isadjusted based on a detected PDCCH with DCI format 0/4 intended for theUE in subframe n-4 410, the HARQ-ACK bits may be constructed for thePUSCH in subframe n 420 using several different pieces of information.In some embodiments, this may include ordering of the configured servingcells. The configured serving cell may be ordered, for example, from 1to C based on the value of the cell ID, assuming a given UE isconfigured with C serving cells. The value of the DAI in DCI format1/1A/1B/1D/2/2A/2B/2C/2D V_(DAI,k) ^(DL), may indicate the accumulatednumber of EPDCCH transmissions up to the present serving cell k withinthe configured serving cells and may be updated from serving cell toserving cell. As shown in FIG. 4, the value of the DAI in DCI formats1/1A/1B/1D/2/2A/2B/2C/2D, V_(DAI,k) ^(DL), may thus be 6 (seven less theSPS CC).

The UE may perform spatial HARQ-ACK bundling across multiple codewordswithin a downlink subframe by a logical AND operation of allcorresponding individual HARQ-ACKs. The total number of HARQ-ACK bitsO^(ACK) may be calculated in some embodiments as follows:O ^(ACK) =W _(DAI) ^(UL) +N┌(U−W _(DAI) ^(UL))/N┐  (1)where:

-   -   U denotes the total number of received PDSCH(s) and PDCCH        transmission indicating a downlink SPS release detected by the        UE in subframe n-4 across all serving cells.    -   W_(DAI) ^(UL) is determined by the DAI in DCI format 0/4        according to Table 4 in subframe n-4 corresponding to different        bits number of DAI field.        -   N=4, 8 or 16 respectively corresponding to a 2-bit, 3-bit,            or 4-bit DAI field.        -   ┌ ┐ is a ceiling operator

TABLE 4 Value of W_(DAI) ^(UL) determined by the 2/3/4-bit DAI field inDCI format 0/4

The UE may not transmit a HARQ-ACK signal on a PUSCH if the UE does notreceive a PDSCH or PDCCH transmission indicating a downlink SPS releasein subframe n-4. Thus, in some embodiments, the UE may transmit aHARQ-ACK signal on a PUSCH only if the UE receives a PDSCH or PDCCHtransmission indicating a downlink SPS release in subframe n-4. Similarto the above. W_(DAI) ^(UL)=4, 8 or 16 corresponds to 2/3/4-bit DAI inDCI format 0/4.

The ordering of the HARQ-ACK bits may also be determined by the UE. Aspatially bundled HARQ-ACK for a PDSCH with a corresponding PDCCH or fora PDCCH indicating a downlink SPS release in subframe n-4 may beassociated with O_(B(k)−1) ^(ACK) where B(k) is derived based on the DAIvalue V_(DAI,k) ^(DL) in DCI format 1/1A/1B/1D/2/2A/2B/2C/2D detected insubframe n-4 in the k-th serving cell as specified in Table 1, 2 or 3 insubframe n-4.B(k)=V _(DAI,k) ^(DL) +N┌(U _(k) −V _(DAI,k) ^(DL))/N┐  (2)

where U_(k) denotes the total number of received PDSCH(s) and PDCCHtransmissions indicating a downlink SPS release detected by the UE insubframe n-4 across serving cells 1, 2, . . . k and ┌ ┐ is a ceilingoperator. The definition of N may be same as above.

When the number of downlink SPS releases is not zero (i.e., N_(SPS)>0),the HARQ-ACK associated with a PDSCH without a corresponding PDCCH maybe mapped to O_(O) _(ACK) ⁻¹ ^(ACK). HARQ-ACK bits without any detectedPDSCH transmission or without a detected PDCCH indicating a downlink SPSrelease may be set to NACK.

FIG. 5 illustrates a HARQ-ACK construction using DAI fields according tosome embodiments. In the subframe shown in FIG. 5, up to 8 CCs 510 maybe aggregated for PDSCH transmission for a given UE in a FDD system,with the CCs having a CC index 512 ranging from 1-8. As shown, the UE isscheduled with a PDSCH transmission in all CCs 510 except CC 2 and CC7,and thus 6 DAIs are associated with the CCs having a PDSCH transmission510. The DAI value V_(DAI,k) ^(DL) 514 in DCI format1/1A/1B/1D/2/2A/2B/2C/2D, again assuming a 2-bit DAI field, for the CCs510 containing a PDSCH transmission runs from 1-4 before repeating. Theaccumulative value, U_(k), 516 and B(k) value 518 each runs from 1-6with increasing CCs 510 containing a PDSCH transmission assuming allPDSCH transmitted by the eNB is detected at the UE. The total HARQ-ACKbits number O^(ACK) may then be calculated from equation (1) asO^(ACK)=6. The UE may thus construct a total of 6 HARQ-ACK bits with aparticular order based on B(k) to transmit over PUSCH.

While the above description focused on FDD systems, a similar mechanismmay be used for TDD systems. FIG. 6 shows TDD legacy DCI formatadjustments according to some embodiments. Constructing reduced overheadHARQ-ACK responses in TDD systems using carrier aggregation with a largeamount of CCs may be achieved in a similar manner as above for FDDsystem. Thus, in some embodiments, to form the new uplink DCI format 0/4610 a new Z bit field 616 of a CC-specific DAI (also referred to asDAI-2 field) may be added to the legacy Rel-13 DCI format 0/4 612 forTDD operation in a manner similar to the above. The legacy Rel-13 DCIformat 0/4 612 for TDD operation may also contain a DAI 614 of length2-bits whose value may represent the total number of subframescontaining PDSCH transmissions assigned to the UE across all of the CCsin the bundling window. Herein, a bundling window may comprise a numberof downlink subframes associated with a single uplink subframe forHARQ-ACK feedback according to a predefined HARQ timing relationship forPDSCH transmission. In some embodiments, the length of the DAI-2 DCIformat 0/4 field 616 may be 2 bits. As above, the DAI-2 field 616 may bepresent in DCI format 0/4, which is mapped onto the UE specific searchspace given by CRC bits scrambled by the C-RNTI. In some embodiments,X=Z to maximize the commonality between FDD and TDD system solutions.The value of the DAI-2 DCI format 0/4 field 616 may represent the totalnumber of serving cells (i.e., carriers) with PDSCH transmissions andwith PDCCH/EPDCCH transmissions indicating a downlink SPS release to thecorresponding UTE within the associated subframes n-k in a bundlingwindow, where kϵK and K is defined in Table 5 The DAI field 614 in DCIformat 0/4 and DAI-2 field 616 in DCI format 0/4 may be encodedseparately to present different meanings but when combined may provideuplink information about both the subframes and the CCs containing PDSCHtransmissions.

TABLE 5 Downlink association set index K: {k₀, k₁, L, k_(M−1)} for TDDUL-DL Subframe n Configuration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 — — 6 — 41 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, 4, 6 — — 3 —— 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, 4, 7 — — — — — —5 — — 13, 12, 9, 8, — — — — — — — 7, 5, 4, 11, 6 6 — — 7 7 5 — — 7 7 —

In a manner similar to the above, a new L-bit DAI-2 field 626 may beadded to the legacy DCI format 1/1A/1B/1D/2/2A/2B/2C/2D 622 to form anew downlink DCI format 1/1A/1B/1D/2/2A/2B/2C/2D 620 in the TDD system.In some embodiments, the length of the L-bit DAI-2 field in the DCIformat 1/1A/1B/1D/2/2A/2B/2C/2D 626 may be 2 bits. The UE may not beexpected to receive DCI format 1/1A/1B/1D/2/2A/2B/2/2D with differentDAI-2 values in any subframe for a given serving cell. The DAI-2 field626 correspondingly may be present in the DCI format used for schedulinga PDSCH transmission (e.g. DCI format 1/1A/1B/1D/2/2A/2B/2C/2D) and ismapped to the UE specific search space given by the CRC bits scrambledby the C-RNTI. The value of the DAI-2 DCI field 626 in the new DCIformat 1/1A/1B/1D/2/2A/2B/2C/2D 620 may indicate the accumulative numberof serving cells providing a PDCCH/EPDCCH(s) transmission with assigneda PDSCH transmission(s) and a PDCCH/EPDCCH transmission indicating adownlink SPS release across all the configured serving cells. The DAI-2field 626 values in one of DCI format 1/1A/1B/1D/2/2A/2B/2C/2D may beupdated from serving cell to serving cell. The legacy Rel-13 DCI format1/1A/1B/1D/2/2A/2B/2C/2D 622 for TDD operation may also contain a legacyDAI 624 of length 2-bits, whose value may represent the accumulativenumber of scheduled PDSCH transmissions within a bundling windowassigned to the UE per each serving cell. As above, the DAI field 624and DAI-2 field 626 in new DCI format 1/1A/1B/1D/2/2A/2B/2C/2D may beencoded separately to present different meanings but when combinedprovide downlink information about both the subframes and the CCscontaining PDSCH transmissions.

The total HARQ-ACK bits number O^(ACK) may, in some embodiments, becalculated as follows.O ^(ACK) =B ₁ ×B ₂  (3)B ₁ =W _(DAI,2) ^(UL) +N┌(U ² −W _(DAI,2) ^(UL))/N┐  (4)B ₂ =W _(DAI) ^(UL)+4┌(U−W _(DAI) ^(UL))/4┐  (5)Where:

-   -   W_(DAI,2) ^(UL) is determined by the DAI-2 DCI format 0/4        according to Table 4 corresponding to different number of bits        of the DAI.    -   U² indicates the total number of serving cells with a received        PDSCH(s) and PDCCH transmission indicating a downlink SPS        release detected by the UE across all serving cells within a        HARQ-ACK bundling window constructed according to Table 5.    -   N=4, 8 or 16, respectively, corresponds to a 2-bit, 3-bit, or        4-bit DAI field.    -   W_(DAI) ^(UL) is determined by the legacy DAI in DCI format 0/4        according to Table 4 corresponding to a 2-bit DAI field.    -   U denotes the maximum value of U_(c) among all the configured        serving cells, U_(c) is the total number of received PDSCHs and        PDCCH transmissions indicating a downlink SPS release in a        HARQ-ACK bundling window on serving cell c.    -   ┌ ┐ is a ceiling operator.

For TDD, the HARQ-ACK feedback bits O_(DAI) _(2(c),0) ^(ACK), O_(DAI)_(2(c),1) ^(ACK), . . . , O_(DAI) ₂ _((c),O) _(c) _(ACK) ⁻¹ for the c-thserving cell are constructed following equation (3), where DAI₂(c) isthe value of the DAI-2 field of the DCI format 1A/1B/1D/1/2/2A/2B/2C/2Ddetected in the c-th serving cell and O_(c) ^(ACK)=B₂, where B₂ iscalculated as above in equation (5).

For TDD UL-DL configuration 1-6, the HARQ-ACK for a PDSCH transmissionwith a corresponding PDCCH or for a PDCCH indicating downlink SPSrelease in subframe n-k in c-th serving cell may be associated withO_(DAI) ₂ _((c),DAI(k,c)−1) ^(ACK), where DAI₂(c) and DAI(k,c) are thevalues of the DAI-2 field and 2 bit DAI field in DCI format1A/18/1D/1/2/2A/2B/2C/2D detected in subframe n-k in the c-th servingcell.

FIG. 7 illustrates DAI-2 and DAI field settings according to someembodiments. In particular, FIG. 7 illustrates an example of the mannerthe DAI-2 and DAI field 706 values are set in DCI format used forscheduling PDSCH (e.g. DCI format 1A/1B/1D/1/2/2A/2B/2C/2D) in eachcorresponding DL subframe in configured serving cells, given the PDSCHtransmission pattern shown. The HARQ-ACK bundling window 700 of foursubframes in FIG. 7 contains ten aggregated CCs 702, in which subframes704 having indexes n, n+1, n+2 and n+3 are shown. The CCs (i.e. servingcells) 702 in each subframe 704 may include a PDSCH CC 710 that containsa PDSCH transmission or a non-PDSCH CC 712 that does not contain a PDSCHtransmission in any downlink subframe of the HARQ-ACK bundling window700. The first number in the parenthesis of the DAI-2 and DAI fields 706is the DAI-2 value that denotes the accumulative number of all differentCCs 702 containing PDSCH transmissions in at least one subframe 702within the bundling window 700 and may be updated from CC to CC from CC0in the ascending order of the downlink CCs, while the second numberindicates the accumulative number of subframes 704 with PDSCHtransmissions and with a PDCCH/EPDCCH transmission indicating a downlinkSPS release to the corresponding UE of a particular CC 702 within thebundling window 700. Thus, although CC2 in subframe n does not contain aPDSCH transmission, the DAI-2 number of CC3 in subframe n is 3 as CC2contains a PDSCH transmission in at least one other subframe (subframen, n+2 and n+3). As shown in the example of FIG. 7, only CC5, 7 and 9 donot contain a PDSCH transmission in any subframe of the bundling window,resulting in the maximum DAI-2 being 7 Similarly, the maximum number ofsubframes in which any CC contains a PDSCH transmission in the bundlingwindow is 3 (CC 1, 2, 4, 6 and 8, with CC 3 and 10 containing 2 PDSCHtransmissions in different subframes). In this case, there are 19 PDSCHtransmissions across a total of 7 CCs within the bundling window 700, soW_(DAI,2) ^(UL)=W_(DAI) ^(UL)=3 according to Table 4 and its physicalmeaning defined above, U² is 7 (7 CCs), N=4 for a 2 bit DAI-2, and U=3.Thus, B₁=3+4┌(7−3)/4┐=7, B₂=3+4┌(3−3)/4┐=3, and O^(ACK)=21. Accordingly,in this example, the UE provides a PUSCH feedback of 21 HARQ-ACK bits tothe eNB in an ACK/NACK response after performing by a logical ANDoperation of the corresponding individual HARQ-ACKs within a DL orspecial subframe.

FIG. 8 illustrates DAI-2 and DAI determination according to someembodiments. The HARQ-ACK bundling window 800 of four subframes containsten aggregated CCs 802, in which subframes 804 having indexes n, n+1,n+2 and n+3 are shown. The CCs 802 in each subframe 804 include a PDSCHCC 810 that contains a PDSCH transmission or a non-PDSCH CC 812 thatdoes not contain a PDSCH transmission. In particular, in FIG. 8 the newZ-bit DAI-2 field and the 2-bit legacy DAI field in DCI format 0/4 maybe combined to a joint DAI field 806 that indicates the total number ofsubframes with PDSCH transmissions and with a PDCCH/EPDCCH transmissionindicating a downlink SPS release to the corresponding UE within theassociated HARQ-ACK bundling window 800 among all the configured servingcells 802. Thus, as shown, within the associated HARQ-ACK bundlingwindow 800, in each of subframe n, n+1 and n+3, 5 serving cells (CCs)802 contain PDSCH/PDCCH/EPDCCH transmissions, 4 serving cells containPDSCH/PDCCH/EPDCCH transmissions in subframe n+2 Note that the PDSCH CCs810 and non-PDSCH CCs 812 may differ between subframes 804. This resultsin a joint DAI value 806 of 19. Similarly, the L-bits DAI-2 field andthe 2 bit legacy DAI field in DCI format 1A/1B/1D/1/2/2A/2B/2C/2D may becombined to form a joint DAI field 806 that indicates the accumulativenumber of subframes with a PDSCH transmission.

FIG. 9 illustrates a flowchart of a method of using a HARQ-ACKtransmission with reduced overhead in accordance with some embodiments.At operation 902, the UE may receive a PDSCH or PDCCH/EPDCCHtransmission indicating a downlink SPS release. The UE may determinethat the PDSCH or PDCCH/EPDCCH transmission is specifically for the UEas the CRC of the DCI formats transmitted on PDCCH/EPDCCH may bescrambled using the C-RNTI. The PDSCH or PDCCH transmission may bereceived in a particular subframe (subframe n-4).

At operation 904, the UE may determine the DCI format from the PDSCH orPDCCH transmission. The DCI format may include different DAI fieldsincluding a legacy DAI IE used in system or network employing 3GPP LTERelease 12 communications and a multi-bit DAI-2 IE whose value maydepend on the type of transmission (FDD or TDD) as well as the number ofsubframes or serving cells or CCs containing either the PDSCH or PDCCHtransmission indicating a downlink SPS release.

The UE may construct each of the HARQ-ACK bits using the value of theDAI-2 at operation 906. The UE may extract the DAI field value in theDCI format. The UE may determine a total number of serving cells, CCs,or subframes with PDSCH transmissions and with a PDCCH/EPDCCHtransmission indicating a downlink SPS release in the subframe n-4 fromthe DAI value in a FDD DCI format 0/4. The UE may determine anaccumulative number of serving cells, CCs, or subframes with PDSCHtransmissions and with a PDCCH/EPDCCH transmission indicating a downlinkSPS release in the subframe n-4 from the DAI value in a FDD DCI format1/1A/1B/1D/2/2A/2B/2C/2D transmission. Similarly UE may determine atotal number of serving cells or CCs with PDSCH transmissions and with aPDCCH/EPDCCH transmission indicating a downlink SPS release within theassociated subframes n-k in a bundling window from the DAI value in aTDD DCI format 0/4. The UE may also determine an accumulative number ofserving cells or CCs with PDSCH transmissions and with a PDCCH/EPDCCHtransmission indicating a downlink SPS release within the associatedsubframes n-k in a bundling window from the DAI value in a TDD DCIformat 1/1A/1B/1D/2/2A/2B/2C/2D transmission.

After calculating the total number of the HARQ-ACK bits using the aboveequations and tables, the UE may at operation 908 first bundle theHARQ-ACK bits to reduce the size of the overall HARQ-ACK bits. Afterbundling the HARQ-ACK bits by a logical ANDing operation acrosstransport blocks in a downlink subframe or special subframe, the UE maydetermine the ordering of the bundled HARQ-ACK bits to avoid ambiguityin the association between the HARQ-ACK bits and corresponding componentcarriers/transport blocks. Having determined the total number ofHARQ-ACK bits and ordering of the bundled HARQ-ACK bits, the UE mayconstruct the the HARQ-ACK bits string in the appropriate order fortransmission on the PUSCH.

In response to forming the HARQ-ACK transmission, the UE may then atoperation 910 transmit the HARQ-ACK feedback to the eNB. The UE maytransmit an ACK/NACK in the uplink subframe n, four subframes after thePDSCH/PDCCH reception.

Example 1 can include subject matter, such as apparatus of a userequipment device, comprising processing circuitry configured to:configure a transceiver, configured to transmit and receive signals froman enhanced Node-B (eNB), to receive a subframe containing a physicaldownlink control channel (PDCCH) formed in accordance with a firstDownlink Control Information (DCI) format, the DCI format comprising afirst Downlink Assignment Index (DAI) field for Time Division Duplexed(TDD) and Frequency Division Duplexed (FDD) operation; determine,dependent on the DAI, a number and order of Hybrid Automatic RepeatRequest-Acknowledgment (HARQ-ACK) bits to be transmitted on a PhysicalUplink Shared Channel (PUSCH), and configure the transceiver to transmita PUSCH containing the generated HARQ-ACK bits.

Example 2 can include the subject matter of Example 1 and optionallyinclude that the DCI format comprises at least one of a DCI format usedfor PUSCH scheduling and a DCI format used for Physical Downlink SharedChannel (PDSCH) scheduling.

Example 3 can include the subject matter of one or any combination ofExamples 1-2 and optionally include that the DCI format furthercomprises a second DAI field for TDD operation rather than FDDoperation.

Example 4 can include the subject matter of one or any combination ofExamples 1-3 and optionally include that the first DCI format comprisesthe first DAI and a second DCI format used in a Third GenerationPartnership Project Long Term Evolution (3GPP LTE) Release 12 system,the second DCI format comprising the second DAI rather than the firstDAI.

Example 5 can include the subject matter of one or any combination ofExamples 1-4 and optionally include that the first DAI comprises thesecond DAI and a third DAI, a number of bits of the third DAI in a DCIformat used for scheduling PUSCH and in a DCI format used for schedulingPhysical Downlink Shared Channel (PDSCH) are different or same.

Example 6 can include the subject matter of one or any combination ofExamples 1-5 and optionally include that the value of the third DAIfield in the DCI format used for scheduling PUSCH in a particular ULsubframe in a FDD serving cell corresponds to a total number of servingcells with PDSCH transmissions and with a PDCCH or an enhanced PDCCH(EPDCCH) indicating a downlink semi-persistent scheduling (SPS) releasein a corresponding DL subframe four subframes prior to the particular ULsubframe used for the transmission of determined HARQ-ACK bits.

Example 7 can include the subject matter of one or any combination ofExamples 1-6 and optionally include that the value of the third DAI inthe DCI format used for scheduling PDSCH in a particular DL subframe ina FDD or TDD serving cell corresponds to an accumulative number ofPDCCHs and enhanced PDCCHs (EPDCCH) with assigned PDSCH transmissionsand PDCCHs and EPDCCHs indicating a downlink semi-persistent scheduling(SPS) release across all serving cells within a number of DL subframesassociated with a single UL subframe for HARQ-ACKs transmission based ona predefined HARQ timing relationship and shall be updated from servingcell to serving cell.

Example 8 can include the subject matter of one or any combination ofExamples 1-7 and optionally include that the value of the third DAI inthe DCI format used for scheduling PUSCH in a particular UL subframe ina TDD serving cell corresponds to a total number of serving cells withPDSCH transmissions and with a PDCCH or an enhanced PDCCH (EPDCCH)indicating a downlink semi-persistent scheduling (SPS) release to the UEwithin an associated HARQ-ACK bundling window (i.e. a number of DLsubframes associated with the particular UL subframe for HARQ-ACKstransmission) dependent on a predefined HARQ timing relationship.

Example 9 can include the subject matter of one or any combination ofExamples 1-8 and optionally include that the value of the second DAI inthe DCI format used for scheduling PUSCH in a particular UL subframecorresponds to a total number of subframes with PDSCH transmissions andwith a PDCCH or an enhanced PDCCH (EPDCCH) indicating downlinksemi-persistent scheduling (SPS) release to the UE within an associatedHARQ-ACK bundling window among all configured serving cells based on apredefined HARQ timing relationship.

Example 10 can include the subject matter of one or any combination ofExamples 1-9 and optionally include that the value of the second DAI inthe PDSCH DCI format corresponds to an accumulative number of subframeswith PDSCH transmissions and PDCCH/EPDCCH indicating DL SPS releases upto the present subframe within an associated HARQ-ACK bundling windowamong all configured serving cells based on a predefined HARQ timingrelationship.

Example 11 can include the subject matter of one or any combination ofExamples 1-10 and optionally include that a number of HARQ-ACK bits in aPUSCH in subframe n is O^(ACK), and O^(ACK)=W_(DAI) ^(UL)+N┌(U−W_(DAI)^(UL))/N┐, where: U indicates a total number of received PDSCHs andPhysical Downlink Control Channels (PDCCHs) indicating a downlinksemi-persistent scheduling (SPS) release detected by the UE in subframen-4 across all serving cells, W_(DAI) ^(UL) is determined by thedetected value of the third DAI field in DCI format 0/4 in subframe n-4,and N=4, 8 or 16 depending on a number of bits of the third DAI asdefined in previous Tables. ┌X┐ is ceiling function to get the smallestinteger not less than x

Example 12 can include the subject matter of one or any combination ofExamples 1-11 and optionally include that a number of HARQ-ACK bits in aPUSCH in subframe n is O^(ACK), O^(ACK)=B₁×B₂, B₁=W_(DAI,2)^(UL)+N┌(U²−W_(DAI,2) ^(UL))/N┐, and B₂=W_(DAI) ^(UL)+4┌(U−W_(DAI)^(UL))/4┐, where W_(DAI,2) ^(UL) is determined by the value of the thirdDAI in detected DCI format 0/4, U² indicates a total number of servingcells with received PDSCHs and PDCCHs indicating downlinksemi-persistent scheduling (SPS) release detected by the UE across allserving cells within a HARQ-ACK bundling window, N=4, 8 or 16 dependingon a number of bits in the third DAI, W_(DAI) ^(UL) is determined by thesecond DAI, U indicates a maximum value of U_(c) among all configuredserving cells, and U_(c) is a total number of received PDSCHs and PDCCHsindicating a downlink SPS release in the HARQ-ACK bundling window.

Example 13 can include the subject matter of one or any combination ofExamples 1-12 and optionally include that an antenna configured toprovide communications between the transceiver and the serving cells.

Example 14 can include subject matter including a non-transitorycomputer-readable storage medium that stores instructions for executionby one or more processors of user equipment (UE) to communicate with aplurality of serving cells, the one or more processors to configure theUE to: receive a subframe containing a physical downlink control channel(PDCCH) formed in accordance with a first Downlink Control information(DCI) format, the DCI format comprising a first Downlink AssignmentIndex (DAI) for Time Division Duplexed (TDD) and Frequency DivisionDuplexed (FDD) operation added to a legacy second DCI format used in aThird Generation Partnership Project Long Term Evolution (3GPP LTE)Release 12 or earlier system, the second DCI format comprising thesecond DAI rather than the first DAI; determine, dependent on the valueof the first DAI, a number and order of Hybrid Automatic RepeatRequest-Acknowledgment (H ARQ-ACK) bits to be transmitted on a PhysicalUplink Shared Channel (PUSCH); and transmit a PUSCH containing thedetermined HARQ-ACK bits.

Example 15 can include the subject matter of Example 14 and optionallyinclude that the first DAI field comprises and a second DAI for TDDoperation and a third DAI field, and the number of bits of the third DAIin a DCI format used for scheduling PUSCH and in a DCI format used forscheduling PDSCH are same or different.

Example 16 can include the subject matter of one or any combination ofExamples 14-15 and optionally include that the third DAI in the DCIformat used for scheduling PUSCH in a particular subframe in a FDDserving cell corresponds to a total number of serving cells with PDSCHtransmissions and with a PDCCH or an enhanced PDCCH (EPDCCH) indicatinga downlink semi-persistent scheduling (SPS) release in a correspondingDL subframe four subframes prior to the particular UL subframe used forthe transmission of determined HARQ-ACK bits.

Example 17 can include the subject matter of one or any combination ofExamples 14-16 and optionally include that the third DAI in the DCIformat used for scheduling PDSCH in a particular DL subframe in a FDD orTDD serving cell corresponds to an accumulative number of PDCCHs andenhanced PDCCHs (EPDCCH) with assigned PDSCH transmissions and PDCCHsand EPDCCHs indicating a downlink semi-persistent scheduling (SPS)release across all serving cells in a bundling window.

Example 18 can include the subject matter of one or any combination ofExamples 14-17 and optionally include that the value of the third DAI inthe DCI format used for scheduling PUSCH in a particular UL subframe ina TDD serving cell corresponds to a total number of serving cells withPDSCH transmissions and with a PDCCH or an enhanced PDCCH (EPDCCH)indicating a downlink semi-persistent scheduling (SPS) release to the UEwithin an associated HARQ-ACK bundling window based on a predefinedHARQ-ACK timing relationship.

Example 19 can include the subject matter of one or any combination ofExamples 14-18 and optionally include that the value of the second DAIin the DCI format used for scheduling PUSCH in a particular UL subframecorresponds to a total number of subframes with PDSCH transmissions andwith a PDCCH or an enhanced PDCCH (EPDCCH) indicating downlinksemi-persistent scheduling (SPS) release to the UE within an associatedHARQ-ACK bundling window among all configured serving cells dependent ona predefined HARQ timing relationship.

Example 20 can include the subject matter of one or any combination ofExamples 14-19 and optionally include that the value of the second DAIin the DCI format used for scheduling PDSCH corresponds to anaccumulative number of subframes with PDSCH transmissions andPDCCH/EPDCCH indicating DL SPS releases up to the present subframewithin an associated HARQ-ACK bundling window for a serving cell basedon a predefined HARQ timing relationship.

Example 21 can include subject matter of an apparatus of an eNBconfigured to communicate with user equipment (UE), the apparatuscomprising: processing circuitry configured to: configure a transceiverto transmit to a first UE a subframe containing a physical downlinkcontrol channel (PDCCH) formed in accordance with a first DownlinkControl information (DCI) format, the first DCI format comprising afirst Downlink Assignment Index (DAI) field for Time Division Duplexed(TDD) and Frequency Division Duplexed (FDD) operation; configure thetransceiver to transmit to a second UE a subframe containing a PDCCHformed in accordance with a second DCI format, the second DCI formatcomprising a second DAI field for TDD operation; and configure thetransceiver to receive Hybrid Automatic Repeat Request-Acknowledgment(HARQ-ACK) responses on Physical Uplink Shared Channels (PUSCHs) fromthe first and second UEs, wherein the HARQ-ACK response from the firstUE has a reduced size compared with the HARQ-ACK response from thesecond UE based on the first and second DCI formats.

Example 22 can include the subject matter of Example 21 and optionallyinclude that the first DAI comprises the second DAI and a third DAI, andthe number of bits of the third DAI in a DCI format used for schedulingPUSCH and in a DCI format used for scheduling Physical Downlink SharedChannel (PDSCH) are same or different.

Example 23 can include the subject matter of one or any combination ofExamples 21-22 and optionally include that the third DAI in the DCIformat used to schedule PUSCH in a particular subframe in a FDD servingcell corresponds to a total number of serving cells with PDSCHtransmissions and with a PDCCH or an enhanced PDCCH (EPDCCH) indicatinga downlink semi-persistent scheduling (SPS) release in a subframe foursubframes prior to the particular subframe, the value of the third DAIin the DCI format used for scheduling PDSCH in a particular subframecorresponds to an accumulative number of PDCCHs and EPDCCH with assignedPDSCH transmissions and PDCCHs and EPDCCHs indicating a SPS release inserving cells in the particular subframe, the value of the third DAI inthe DCI format used for scheduling PUSCH in a particular UL subframe ina TDD serving cell corresponds to a total number of serving cells withPDSCH transmissions and with a PDCCH or an EPDCCH indicating a downlinkSPS release to the UE within an associated HARQ-ACK bundling windowdependent on a predefined HARQ timing relationship, the second DAI inthe DCI format used for scheduling PUSCH in a particular subframecorresponds to a total number of subframes with PDSCH transmissions andwith a PDCCH or an EPDCCH indicating downlink SPS release to the UEwithin an associated HARQ-ACK bundling window among all configuredserving cells dependent on a predefined HARQ timing relationship, or thesecond DAI in the DCI format used for scheduling PDSCH corresponds to anaccumulative number of subframes with PDSCH transmissions andPDCCH/EPDCCH indicating DL SPS releases up to the present subframewithin an associated HARQ-ACK bundling window on a serving celldependent on a predefined HARQ timing relationship.

Although an embodiment has been described with reference to specificexample embodiments, it will be evident that various modifications andchanges may be made to these embodiments without departing from thebroader spirit and scope of the present disclosure. Accordingly, thespecification and drawings are to be regarded in an illustrative ratherthan a restrictive sense. The accompanying drawings that form a parthereof show, by way of illustration, and not of limitation, specificembodiments in which the subject matter may be practiced. Theembodiments illustrated are described in sufficient detail to enablethose skilled in the art to practice the teachings disclosed herein.Other embodiments may be utilized and derived therefrom, such thatstructural and logical substitutions and changes may be made withoutdeparting from the scope of this disclosure. This Detailed Description,therefore, is not to be taken in a limiting sense, and the scope ofvarious embodiments is defined only by the appended claims, along withthe full range of equivalents to which such claims are entitled.

Such embodiments of the inventive subject matter may be referred toherein, individually and/or collectively, by the term “invention” merelyfor convenience and without intending to voluntarily limit the scope ofthis application to any single invention or inventive concept if morethan one is in fact disclosed. Thus, although specific embodiments havebeen illustrated and described herein, it should be appreciated that anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more” In this document,the term “or” is used to refer to a nonexclusive or, such that “A or B”includes “A but not B.” “B but not A,” and “A and B,” unless otherwiseindicated. In this document, the terms “including” and “in which” areused as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, UE,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third,” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

The Abstract of the Disclosure is provided to comply with 37 C.F.R §1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment.

What is claimed is:
 1. An apparatus of a user equipment (UE)configurable for Hybrid Automatic Repeat Request-Acknowledgment(HARQ-ACK) reporting, the apparatus comprising: a memory; and processingcircuitry in communication with the memory, the processing circuitryconfigured to: decode a Radio Resource Control (RRC) message thatconfigures the UE for HARQ-ACK reporting; and decode a Downlink ControlInformation (DCI) of a Physical Downlink Control Channel (PDCCH) of aserving cell, the DCI comprising one of a plurality of formats and aDownlink Assignment Index (DAI); wherein as part of the HARQ-ACKreporting, the processing circuitry is configured to: determine HARQ-ACKfeedback for transmission in a Physical Uplink Shared Channel (PUSCH),the HARQ-ACK feedback comprising a bit sequence of HARQ-ACK bits storedin the memory, a number of the HARQ-ACK bits and the bit sequence of theHARQ-ACK bits dependent on a value of the DAI; and encode the HARQ-ACKbits for transmission on the PUSCH, the bits in accordance with the bitsequence, wherein: the number of HARQ-ACK bits is O^(ACK) and isdependent on a number of received Physical Downlink Shared Channels(PDSCHs) and Physical Downlink Control Channels (PDCCHs) indicating adownlink semi-persistent scheduling (SPS) release concatenated acrossserving cells in at least one subframe, DCI format 0 or DCI format 4uses a 2 bit DAI, DCI format 1/1A/1B/1D/2/2A/2B/2C/2D uses a 0, 2 or 4bit DAI that is configured by higher layer, and the 4 bit DAI comprisesa 2-bit counter DAI and a 2-bit total DAI, in which: the 2-bit counterDAI denotes an accumulative number of serving cells with PDSCHtransmissions associated with a PDCCH or EPDCCH and a serving cell witha PDCCH or EPDCCH indicating the downlink SPS release, up to the presentserving cell in increasing order of serving cell index, and the 2-bittotal DAI in which the 2-bit total DAI denotes a total number of servingcells with PDSCH transmissions associated with a PDCCH or EPDCCH and aserving cell with a PDCCH or EPDCCH indicating the downlink SPS release.2. The apparatus of claim 1, wherein: for Frequency Division Duplexed(FDD) transmissions, the PDCCH is in subframe n-4 and the PUSCH is insubframe n.
 3. The apparatus of claim 1, wherein: for Time DivisionDuplexed (TDD) transmissions, the PUSCH is in the subframe n and thePDCCHs are in subframes n-k, where kϵK and K is given by: UL-DL Subframen Configuration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 — — 6 — 4 1 — — 7, 6 4 —— — 7, 6 4 — 2 — — 8, 7, — — — — 8, — — 4, 6 7, 4, 6 3 — — 7, 6, 6, 5 5,4 — — — — — 11 4 — — 12, 8, 6, — — — — — — 7, 11 5, 4, 7 5 — — 13, — — —— — — — 12, 9, 8, 7, 5, 4, 11, 6 6 — — 7 7 5 — — 7 7 —.


4. The apparatus of claim 1, wherein: a combination of the counter DAIand the total DAI for Frequency Division Duplexed (FDD) is dependent onthe number of serving cells with a PDSCH transmission associated with aPDCCH or EPDCCH and current serving cell with a PDCCH or EPDCCHindicating downlink SPS release and each combination is duplicated fordifferent numbers of serving cells with a PDSCH transmission associatedwith a PDCCH or EPDCCH and current serving cell with a PDCCH or EPDCCHindicating downlink SPS release.
 5. The apparatus of claim 1, wherein: avalue of the counter DAI (V_(DAI,c) ^(DL)) and of the total DAI(V_(T-DAI) ^(DL)) for FDD is: DAI Number of serving cells with PDSCHtransmission MSB, V_(C-DAI,c) ^(DL) or associated with PDCCH/EPDCCH andserving cell LSB V_(T-DAI) ^(DL) with PDCCH/EPDCCH indicating DL SPSrelease 0, 0 1 1 or 5 or 9 or 13 or 17 or 21 or 25 or 29 0, 1 2 2 or 6or 10 or 14 or 18 or 22 or 26 or 30 1, 0 3 3 or 7 or 11 or 15 or 19 or23 or 27 or 31 1, 1 4 0 or 4 or 8 or 12 or 16 or 20 or 24 or 28 or
 32.


6. The apparatus of claim 1, wherein: the number of HARQ-ACK bits isdependent on the number of received PDSCHs and PDCCHs indicating thedownlink SPS release concatenated across serving cells in a singlesubframe for Frequency Division Duplexed (FDD) and in multiple subframesfor Time Division Duplexed (TDD).
 7. The apparatus of claim 1, wherein:${O^{ACK} = {W_{DAI}^{UL} + {N\left\lceil \frac{\left( {U - W_{DAI}^{UL}} \right)}{N} \right\rceil}}},$where: ┌x┐ is a ceiling function to obtain a smallest integer not lessthan x, U indicates a total number of received PDSCHs and PDCCHsindicating the downlink SPS release in a single previous subframe acrossall serving cells, W_(DAI) ^(UL) is a detected value of the DAIaccording to a predefined table, and N depends on a bit number of theDAI.
 8. The apparatus of claim 7, wherein: a number of information bitsof the DAI in a DCI format to schedule the PUSCH and a number ofinformation bits in a DCI format to schedule a Physical Downlink SharedChannel (PDSCH) are different.
 9. The apparatus of claim 7, wherein: anumber of information bits of the DAI in a DCI format to schedule thePUSCH and a number of information bits in a DCI format to schedule aPhysical Downlink Shared Channel (PDSCH) are the same.
 10. The apparatusof claim 7, wherein the processing circuitry is configured to: generatea number of HARQ-ACK bits in a PUSCH with spatial HARQ-ACK bundlingacross multiple codewords within a downlink subframe by a logical ANDoperation.
 11. The apparatus of claim 10, wherein: a spatially bundledHARQ-ACK bit for a Physical Downlink Shared Channel (PDSCH) with acorresponding PDCCH or for a PDCCH indicating a downlink SPS release insubframe n-4 is associated with O_(B(k)−1) ^(ACK) where B(k) is derivedbased on a value of DAI V_(DAI,k) ^(DL) in a DCI format to schedule aPDSCH detected in subframe n-4 in the k-th serving cell based on apredefined table depending on a number of bits of the third DAI field,B(k)=V _(DAI,k) ^(DL) +N┌(U _(k) −V _(DAI,k) ^(DL))/N┐ where: U_(k)denotes a total number of received PDSCHs and PDCCH indicating adownlink SPS release detected by the UE in subframe n-4 cross allserving cells, and N=4, 8 or 16 corresponding to a 2-bit, 3-bit and4-bit DAI respectively.
 12. An apparatus of an evolved NodeB (eNB), theapparatus comprising: a memory; and processing circuitry incommunication with the memory, the processing circuitry configured to:encode, for transmission to a user equipment (UE), a Downlink ControlInformation (DCI) of a Physical Downlink Control Channel (PDCCH) and aPhysical Downlink Shared Channel (PDSCH) indicating a downlinksemi-persistent scheduling (SPS) release in different serving cells forFrequency Division Duplexed (FDD) and in multiple subframes of aparticular serving cell for Time Division Duplexed (TDD), the DCIcomprising one of a plurality of formats and a Downlink Assignment Index(DAI); and decode Hybrid Automatic Repeat Request-Acknowledgment(HARQ-ACK) feedback transmitted from the UE in a Physical Uplink SharedChannel (PUSCH), the HARQ-ACK feedback comprising a bit sequence ofHARQ-ACK bits stored in the memory, a number of the HARQ-ACK bits andthe bit sequence of the HARQ-ACK bits dependent on a value of the DAI,wherein: the number of HARQ-ACK bits in a present subframe is O^(ACK)and is dependent a total number of PDSCHs and PDCCHs indicating thedownlink SPS release concatenated across all serving cells in a singlesubframe for FDD and in multiple subframes for TDD, a number of bits ofthe DAI is dependent on the DCI format, DCI format 0 or DCI format 4uses a 2 bit DAI, DCI format 1/1A/1B/1D/2/2A/2B/2C/2D uses a 0, 2 or 4bit DAI that is configured by higher layer, and the 4 bit DAI comprisesa 2-bit counter DAI and a 2-bit total DAI, in which: the 2-bit counterDAI denotes an accumulative number of serving cells with PDSCHtransmissions associated with a PDCCH or EPDCCH and a serving cell witha PDCCH or EPDCCH indicating the downlink SPS release, up to the presentserving cell in increasing order of serving cell index, and the 2-bittotal DAI in which the 2-bit total DAI denotes a total number of servingcells with PDSCH transmissions associated with a PDCCH or EPDCCH and aserving cell with a PDCCH or EPDCCH indicating the downlink SPS release.13. The apparatus of claim 12, wherein: for FDD transmissions, the PDCCHis in subframe n-4 and the PUSCH is in subframe n.
 14. The apparatus ofclaim 12, wherein: for TDD transmissions, the PUSCH is in the subframe nand the PDCCHs are in subframes n-k, where kϵK and K is given by: UL-DLSubframe n Configuration 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 — — 6 — 4 1 — —7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, 4, 6 — — 3 — — 7,6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 7, 11 6, 5, 4, 7 — — — — — — 5 —— 13, 12, 9, 8, — — — — — — — 7, 5, 4, 11, 6 6 — — 7 7 5 — — 7 7 —.


15. The apparatus of claim 12, wherein: a combination of the counter DAIand the total DAI for FDD is dependent on the number of serving cellswith a PDSCH transmission associated with a PDCCH or EPDCCH and currentserving cell with a PDCCH or EPDCCH indicating downlink SPS release andeach combination is duplicated for different numbers of serving cellswith a PDSCH transmission associated with a PDCCH or EPDCCH and currentserving cell with a PDCCH or EPDCCH indicating downlink SPS release. 16.The apparatus of claim 12, wherein: a value of the counter DAI(V_(C-DAI,c) ^(DL)) and of the total DAI (V_(T-DAI) ^(DL)) for FDD is:DAI Number of serving cells with PDSCH transmission MSB, V_(C-DAI,c)^(DL) or associated with PDCCH/EPDCCH and serving cell LSB V_(T-DAI)^(DL) with PDCCH/EPDCCH indicating DL SPS release 0, 0 1 1 or 5 or 9 or13 or 17 or 21 or 25 or 29 0, 1 2 2 or 6 or 10 or 14 or 18 or 22 or 26or 30 1, 0 3 3 or 7 or 11 or 15 or 19 or 23 or 27 or 31 1, 1 4 0 or 4 or8 or 12 or 16 or 20 or 24 or 28 or
 32.


17. A non-transitory computer-readable storage medium that storesinstructions for execution by one or more processors of a user equipment(UE) configurable for Hybrid Automatic Repeat Request-Acknowledgment(HARQ-ACK) reporting, the instructions, when executed by the one or moreprocessors, cause the one or more processors to: decode a Radio ResourceControl (RRC) message that configures the UE for HARQ-ACK reporting; anddecode a Downlink Control Information (DCI) of a Physical DownlinkControl Channel (PDCCH) of a serving cell, the DCI comprising one of aplurality of formats and a Downlink Assignment Index (DAI); wherein aspart of the HARQ-ACK reporting, the instructions, when executed by theone or more processors, cause the one or more processors to: determineHARQ-ACK feedback for transmission in a Physical Uplink Shared Channel(PUSCH), the HARQ-ACK feedback comprising a bit sequence of HARQ-ACKbits stored in the memory, a number of the HARQ-ACK bits and the bitsequence of the HARQ-ACK bits dependent on a value of the DAI; andencode the HARQ-ACK bits for transmission on the PUSCH, the bits inaccordance with the bit sequence, wherein: the number of HARQ-ACK bitsis O^(ACK) and is dependent on a number of received Physical DownlinkShared Channels (PDSCHs) and Physical Downlink Control Channels (PDCCHs)indicating a downlink semi-persistent scheduling (SPS) releaseconcatenated across serving cells in at least one subframe, DCI format 0or DCI format 4 uses a 2 bit DAI, DCI format 1/1A/1B/1D/2/2A/2B/2C/2Duses a 0, 2 or 4 bit DAI that is configured by higher layer, and the 4bit DAI comprises a 2-bit counter DAI and a 2-bit total DAI, in which:the 2-bit counter DAI denotes an accumulative number of serving cellswith PDSCH transmissions associated with a PDCCH or EPDCCH and a servingcell with a PDCCH or EPDCCH indicating the downlink SPS release, up tothe present serving cell in increasing order of serving cell index, andthe 2-bit total DAI in which the 2-bit total DAI denotes a total numberof serving cells with PDSCH transmissions associated with a PDCCH orEPDCCH and a serving cell with a PDCCH or EPDCCH indicating the downlinkSPS release.
 18. The medium of claim 17, wherein: a combination of thecounter DAI and the total DAI for Frequency Division Duplexed (FDD) isdependent on the number of serving cells with a PDSCH transmissionassociated with a PDCCH or EPDCCH and current serving cell with a PDCCHor EPDCCH indicating downlink SPS release and each combination isduplicated for different numbers of serving cells with a PDSCHtransmission associated with a PDCCH or EPDCCH and current serving cellwith a PDCCH or EPDCCH indicating downlink SPS release.
 19. The mediumof claim 17, wherein: a value of the counter DAI (V_(C-DAI,c) ^(DL)) andof the total DAI (V_(T-DAI) ^(DL)) for FDD is: DAI V_(C−DAI,c) ^(DL)Number of serving cells with PDSCH transmission MSB, or associated withPDCCH/EPDCCH and serving cell LSB V_(T−DAI) ^(DL) with PDCCH/EPDCCHindicating DL SPS release 0, 0 1 1 or 5 or 9 or 13 or 17 or 21 or 25 or29 0, 1 2 2 or 6 or 10 or 14 or 18 or 22 or 26 or 30 1, 0 3 3 or 7 or 11or 15 or 19 or 23 or 27 or 31 1, 1 4 0 or 4 or 8 or 12 or 16 or 20 or 24or 28 or
 32.


20. The medium of claim 17, wherein:${O^{ACK} = {W_{DAI}^{UL} + {N\left\lceil \frac{\left( {U - W_{DAI}^{UL}} \right)}{N} \right\rceil}}},$where: ┌x┐ is a ceiling function to obtain a smallest integer not lessthan x, U indicates a total number of received PDSCHs and PDCCHsindicating the downlink SPS release in a single previous subframe acrossall serving cells, W_(DAI) ^(UL) is a detected value of the DAIaccording to a predefined table, and N depends on a bit number of theDAI.